Showing papers by "Frank E. Speizer published in 2005"
TL;DR: Extended-duration work shifts, which are currently sanctioned by the Accreditation Council for Graduate Medical Education, pose safety hazards for interns and have implications for medical residency programs, which routinely schedule physicians to work more than 24 consecutive hours.
Abstract: Background Long work hours and work shifts of an extended duration (≥24 hours) remain a hallmark of medical education in the United States. Yet their effect on health and safety has not been evaluated with the use of validated measures. Methods We conducted a prospective nationwide, Web-based survey in which 2737 residents in their first postgraduate year (interns) completed 17,003 monthly reports that provided detailed information about work hours, work shifts of an extended duration, documented motor vehicle crashes, near-miss incidents, and incidents involving involuntary sleeping. Results The odds ratios for reporting a motor vehicle crash and for reporting a near-miss incident after an extended work shift, as compared with a shift that was not of extended duration, were 2.3 (95 percent confidence interval, 1.6 to 3.3) and 5.9 (95 percent confidence interval, 5.4 to 6.3), respectively. In a prospective analysis, every extended work shift that was scheduled in a month increased the monthly risk of a mo...
829 citations
TL;DR: Exposure to summertime air pollution and heart rate variability was examined in a panel study of 28 elderly subjects and particles, especially from traffic, are associated with disturbances of autonomic control of the heart.
Abstract: Background: Particulate air pollution has been associated with increased cardiovascular deaths and hospital admissions. To help understand the mechanisms, the types of particles most involved, and the types of persons most susceptible, the association between exposure to summertime air pollution and heart rate variability (HRV) was examined in a panel study of 28 elderly subjects.
Methods: Subjects were seen once a week for up to 12 weeks and HRV (SDNN, r-MSSD, PNN50, low frequency/high frequency ratio (LFHFR)) was measured for approximately 30 minutes at each session using a defined protocol. Temperature, day of the week, and hour of the day were controlled, and dummy variables for each subject were controlled for subject specific risk factors.
Results: PM2.5 was associated with r-MSSD (–10.1% change for an interquartile range (IQR) increase in exposure (95% CI –2.8 to –16.9)) and PNN50, but stronger associations were seen with black carbon, an indicator of traffic particles, which was also associated with SDNN (–4.6% per IQR (95% CI –2.0 to –7.2)) and LFHFR. Secondary particles were more weakly associated with r-MSSD, as was ozone. No associations were seen with SO2 or NO2. CO had similar patterns of association to black carbon, which disappeared after controlling for black carbon. Black carbon had a substantially higher effect on SDNN in subjects who had had a previous myocardial infarction (–12.7%, 95% CI –5.7 to –19.25).
Conclusions: Particles, especially from traffic, are associated with disturbances of autonomic control of the heart.
292 citations
TL;DR: The authors found that interquartile range increases in 24-hour moving average particulate matter less than 2.5 mum in aerodynamic diameter and ozone were associated with 19% and 21% increased risks of ventricular arrhythmia, respectively.
Abstract: The authors evaluated the association between ventricular arrhythmias detected by implantable cardioverter defibrillators and ambient air pollution concentrations in the hours immediately before the arrhythmia. Patients given implantable cardioverter defibrillators at the New England Medical Center in Boston, Massachusetts, between mid-1995 and 1999 who lived within 40 km of a central monitoring site (n = 203) were followed until July 2002. The authors used a case-crossover design to study the association between ambient air pollution and up to 798 confirmed ventricular arrhythmias among 84 subjects. The authors found that interquartile range increases in 24-hour moving average particulate matter less than 2.5 mum in aerodynamic diameter and ozone were associated with 19% and 21% increased risks of ventricular arrhythmia, respectively. For each, there was evidence of a linear exposure response, and the associations appeared independent. These associations were stronger than associations with mean concentrations on the same calendar day and previous calendar days. The authors did not find associations with pollutant concentrations less than 24 hours before the arrhythmia. Cases with a prior ventricular arrhythmia within 72 hours had greater risk associated with air pollutants than did cases without a recent arrhythmia. These results confirm previous findings and suggest that matching of pollution periods to arrhythmias is important in detecting such associations.
229 citations
TL;DR: Findings indicate that interns commuting after an extended work shift are more than twice as likely to have a motor vehicle crash than those returning from a nonextended shift, which is a serious but preventable safety hazard for both the interns themselves and other motorists.
Abstract: It is not uncommon for interns in the United States to work extended shifts of 24 hours or longer. The marked increase in fatigue-related crashes and trucker deaths has been related to consecutive driving hours, prompting this survey of interns nationwide to detect any associations among work hours, extended shifts, and driving safety. A web-based survey was completed by 2737 interns, 80% of those receiving it. They completed 19,740 monthly reports of work hours, motor vehicle crashes, and near misses, as well as episodes of involuntary sleep. Participants were similar demographically to all interns matched through the National Resident Matching Program in 2002. Just over half the respondents were female. The mean age was 28 years. Nearly 80% were in medical specialties.
The interns averaged 71 hours in the hospital each week and were awake for all but 3 hours. They spent an additional 4 hours weekly working or studying outside the hospital. Days off per month—including weekends, holidays, and allocated time off—averaged 6.5. The average number of extended work shifts per month was 4, and their average duration was 32 hours. In more than 85% of monthly surveys, the interns reported having worked extended shifts without night-float coverage. The longest time of continuous work averaged 28 hours. There were reports of 320 motor vehicle crashes, 133 of which were consequential (led to emergency treatment, caused at least $1000 in property damage, or prompted filing of a police report). The risk of a crash or near miss was significantly greater for interns commuting from work after an extended shift than after a nonextended shift. Every extended shift that was scheduled per month increased the monthly rate of motor vehicle crashes by 9% and increased crashes on the commute from work by 16%. The risk of falling asleep while driving or when stopped in traffic also rose significantly with the number of extended shifts per month.
These findings indicate that interns commuting after an extended work shift are more than twice as likely to have a motor vehicle crash than those returning from a nonextended shift. This is a serious but preventable safety hazard for both the interns themselves and other motorists. Findings from other studies suggest that working an extended shift predisposes to failure of attention and to serious medical errors.
206 citations
TL;DR: Although some evidence for replication was found for SFTPB and HMOX1, none of the previously published COPD genetic associations was convincingly replicated across both study designs.
Abstract: Case-control studies have successfully identified many significant genetic associations for complex diseases, but lack of replication has been a criticism of case-control genetic association studies in general. We selected 12 candidate genes with reported associations to chronic obstructive pulmonary disease (COPD) and genotyped 29 polymorphisms in a family-based study and in a case-control study. In the Boston Early-Onset COPD Study families, significant associations with quantitative and/or qualitative COPD-related phenotypes were found for the tumor necrosis factor (TNF)-α −308G>A promoter polymorphism (P A polymorphism was not significant. In addition, the microsomal epoxide hydrolase “fast” allele (EPHX1 His139Arg) was significantly associated in the case-control study (P = 0.03). Although some evidence for replication was found for SFTPB and HMOX1, none of the previously published COPD genetic associations was convincingly replicated across both study designs.
191 citations
TL;DR: Diagnosis of hypertension, higher BMI, and increasing pack-years of smoking appear to independently increase the risk of renal cell carcinoma.
Abstract: Objective:We prospectively investigated the independent association of hypertension, thiazide use, body mass index, weight change, and smoking with the risk of renal cell carcinoma among men and women using biennial mailed questionnaires.
139 citations
TL;DR: Results suggest that the G773D variant of human elastin confers structural and functional consequences relevant to the pathogenesis of COPD.
Abstract: We describe a novel variant in the terminal exon of human elastin, c.2318 G>A, resulting in an amino acid substitution of glycine 773 to aspartate (G773D) in a pedigree with severe early-onset chronic obstructive pulmonary disease (COPD). Transfection studies with elastin cDNAs demonstrate that the glycine to aspartate change compromises the ability of the mutant protein to undergo normal elastin assembly. Other functional consequences of this amino acid substitution include altered proteolytic susceptibility of the C-terminal region of elastin and reduced interaction of the exon 36 sequence with matrix receptors on cells. These results suggest that the G773D variant confers structural and functional consequences relevant to the pathogenesis of COPD.
73 citations